feat(class/audio): rework TUH_AUDIO into a WASAPI/ALSA-like stream API

Provide a high-level audio streaming API over UAC 1.0 devices while
keeping the USB topology private: applications select supported
{format, sample_rate, channels} configurations per logical stream, and
the driver owns the mapping to AS interface, alternate setting, and
endpoint.

- One logical stream per direction per instance; multiple AS interfaces
  and alternate settings in a direction are merged into the stream's
  configuration list (discrete tuples; continuous ranges exposed as a
  single configuration at the top rate)
- Asynchronous tuh_audio_configure(): SET_INTERFACE to the selected
  alternate setting, open/reconfigure the endpoint, set the sampling
  frequency when supported, initialize the FIFO and packet scheduler,
  then invoke the completion callback
- Frame-based FIFO streaming: tuh_audio_read()/tuh_audio_write() queue
  whole frames; the driver owns transfer replenishment and fractional
  packet scheduling (44.1 kHz pays back the 0.1 frame/ms remainder via
  an accumulator for exact average pacing)
- tuh_audio_start()/tuh_audio_stop() activate/deactivate the stream
  interface through SET_INTERFACE (alt n / alt 0)

Driver correctness fixes:
- Parse only the AC header's interface collection; MIDI Streaming and
  other subclasses are skipped
- Keep every discrete format as a separate configuration; endpoints are
  opened only for the alternate setting selected by tuh_audio_configure()
- Check tuh_interface_set() return values and SET_INTERFACE transfer
  results instead of ignoring failures
- Validate instance state, direction, buffers, and frame counts in every
  transfer API
- Feature Unit requests use the control's real width (mute/AGC/loudness
  1 byte, others 2 bytes) and convert multibyte values to host order
- Failed/stalled/aborted isochronous transfers reach only the error
  callback, never the capture/playback callbacks

The audio_host example uses the new API: 48 kHz stereo by default,
automatic stream restart on error callbacks, a sine test tone on the
playback stream, and periodic mic-only / spk-only / echo phase switching.

1 files changed, 5 insertions, 27 deletions

diff --git a/examples/host/audio_host/src/main.c b/examples/host/audio_host/src/main.c
index b80cd2938..77c28cf41 100644
--- a/examples/host/audio_host/src/main.c
+++ b/examples/host/audio_host/src/main.c
@@ -35,39 +35,17 @@ int main(void) {
   printf("Connect a USB Audio Device (UAC 1.0) to test\r\n");
 
   // init host stack on configured roothub port
-  tusb_rhport_init_t host_init = {
-    .role = TUSB_ROLE_HOST,
-    .speed = TUSB_SPEED_AUTO
-  };
+  tusb_rhport_init_t host_init = {.role = TUSB_ROLE_HOST, .speed = TUSB_SPEED_AUTO};
   tusb_init(BOARD_TUH_RHPORT, &host_init);
 
   board_init_after_tusb();
-
+  uint32_t last_ms = tusb_time_millis_api();
   while (1) {
     // tinyusb host task
     tuh_task();
     led_blinking_task();
-    audio_app_task();
+    audio_app_task_read();
+    audio_app_task_write();
+    defer_queue_task();
   }
 }
-
-//--------------------------------------------------------------------+
-// TinyUSB Callbacks
-//--------------------------------------------------------------------+
-
-//--------------------------------------------------------------------+
-// Blinking Task
-//--------------------------------------------------------------------+
-void led_blinking_task(void) {
-  const uint32_t interval_ms = 1000;
-  static uint32_t start_ms = 0;
-
-  static bool led_state = false;
-
-  // Blink every interval ms
-  if ( tusb_time_millis_api() - start_ms < interval_ms) return; // not enough time
-  start_ms += interval_ms;
-
-  board_led_write(led_state);
-  led_state = 1 - led_state; // toggle
-}